Photoresists (hereinafter referred to as “resists”) are used in the manufacture of printed circuit boards. A resist is generally formed using a photosensitive film having a resin layer made of a photosensitive resin composition formed on a support base made of a resin film or the like. From the standpoint of reducing environmental burden and production cost, such photosensitive films have begun to be switched from organic solvent developing types to alkali developing types.
When a printed circuit board is manufactured with formation of the resist using a photosensitive film, the photosensitive film is laminated onto the conductive layer of a laminated board having a surface conductive layer made of copper or the like, with its resin layer in contact therewith, and thermocompression bonded. Next, the photosensitive film is exposed to light through a prescribed mask for curing of the exposed sections. A developing solution such as sodium carbonate is then used to remove the unexposed sections (uncured sections) to form a resist having the prescribed pattern. The resist is used as a mask for etching of the conductive layer or plating of the conductive layer, to form a circuit pattern. The resist is then removed using a sodium hydroxide or potassium hydroxide aqueous solution to obtain a printed circuit board.
In this type of printed circuit board manufacturing process, the resist must have excellent adhesiveness for the conductive layer in order to form a satisfactory circuit pattern. That is, if the resist has low adhesiveness for the conductive layer, the resist will tend to readily peel during the plating or etching step. For example, peeling of the resist during plating results in contact of the plating solution on undesired areas of the conductive layer. This causes the obtained circuit pattern to be thicker than the prescribed shape or produces disturbances in the form of the circuit pattern edges, making it difficult to form a satisfactory circuit pattern.
In order to avoid this inconvenience, methods are known for adding benzotriazole compounds to photosensitive resin compositions of resists as a means of improving the adhesiveness of the resists for conductive layers (for example, see Patent documents 1 to 3). These benzotriazole compounds have effects of improving adhesiveness of resin layers onto conductive layers.    [Patent document 1] Japanese Examined Patent Publication SHO No. 50-9177    [Patent document 2] Japanese Examined Patent Publication SHO No. 51-5934    [Patent document 3] U.S. Pat. No. 4,680,249